Available methods

Feedback Service

APNS has a feedback service that you must listen to. Apple states that they monitor providers to ensure that they are listening to this service.

The feedback service simply returns an array of Feedback responses. All tokens provided in the feedback should not be sent to again; unless the device re-registers for push notification. You can use the time in the Feedback response to ensure that the device has not re-registered for push notifications since the last send.